n-Propylethoxysiloxanes, their preparation and use

a technology of n-propylethoxysiloxanes and n-propylethoxysiloxanes, which is applied in the field of n-propylethoxysiloxanes, can solve the problems of poor penetration behavior of active substances into substrates, discoloration of substrate surfaces, and at least unwanted sheen or oily appearance of substrates, and achieves high flash point, good application properties, and high effectiveness.

Inactive Publication Date: 2005-01-11
EVONIK DEGUSSA GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0017]Accordingly, one object of the present invention is to provide a method of hydrophobicizing concrete and other mineral building materials, thereby resulting in a product which is secure against evaporation under standard conditions and which, in particular, possesses a higher flash point than PTEO or IBTEO, possesses good application properties, and is highly effective.

Problems solved by technology

High-viscosity agents for hydrophobicizing mineral surfaces generally lead to poor penetration behavior of the active substance into the substrate, especially in the case of very compact substrates, such as concrete with a low w / c ratio.
Furthermore, active substances having a relatively high degree of oligomerization may result in the discoloration of the substrate surface, this discoloration being caused by the failure of higher oligomers to penetrate the substrate, or else the substrate surface is observed at least to have an unwanted sheen or an oily appearance.
It is complicated and expensive to conduct controlled preparation of such a disiloxane.
Monomeric alkylalkoxysilanes, such as n-propyltriethoxysilane (PTEO), isobutyltriethoxysilane (IBTEO) and octyltriethoxysilane (OCTEO), for example, although they possess a comparatively good penetration behavior, are nevertheless hampered by the drawback that on the basis of their own vapor pressure, they may evaporate, leading to material losses and environmental pollution (VOCs—volatile organic compounds).
Here again, marked evaporation losses are found.
OCTEO is generally prepared by hydrosilylating octene with trichlorosilane and then esterifying the product, which is very complex to do.
However, the quantity available on the market exceeds the demand for PTS and PTEO.

Method used

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  • n-Propylethoxysiloxanes, their preparation and use
  • n-Propylethoxysiloxanes, their preparation and use

Examples

Experimental program
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Effect test

example 1

[0066]Preparation of a Mixture of Oligomeric n-propylsiloxanes From n-propyltriethoxysilane and Water (0.8 mol of Water per Mole of Si) Product Designation VPS 9892

[0067]A 2 liter jacketed stirring apparatus is charged with n-propyltriethoxysilane (PTEO) and this initial charge is heated to approximately 80° C. At this temperature, a mixture of ethanol, water and hydrochloric acid is added dropwise by a dropping funnel. The entire reaction mixture is subsequently boiled at reflux for four hours. Thereafter, the ethanol used and the ethanol released during the hydrolysis are removed by distillation, first at ambient pressure and then in vacuo. The liquid remaining at the bottom is VPS 9892.

Amounts used:PTEO1,120.5gWater76.5gEthanol321gHCl (32% by weight in water)1.5gProduct isolated:VPS 9892 (yield: 97% of theory)780.81g

example 2

[0068]Preparation of a Mixture of Oligomeric n-propylsiloxanes (Hydrolyzed With 0.6 Mol of Water Per Mole of Si)

[0069]A 4 literjacketed stirring apparatus is charged with n-propyltriethoxysilane (PTEO) and this initial charge is heated to approximately 80° C. At this temperature, a mixture of ethanol, water and hydrochloric acid is added dropwise by a dropping funnel. The entire reaction mixture is subsequently boiled at reflux for four hours. Thereafter, the ethanol used and the ethanol released during the hydrolysis are removed by distillation, first at ambient pressure and then in vacuo. The liquid remaining at the bottom is the desired propylsiloxane.

Amounts used:PTEO1,442.7gWater75.6gEthanol1,518gHCl (32% by weight in water)1.58gProduct isolated:Propylsiloxane (yield: 91% of theory)1,030.9g

[0070]Composition by GPC (gel permeation chromatography). By means of GPC, mixtures of different molecular size can be separated. By comparison with a standard, it is possible to determine th...

example 4

[0074]Penetration Behavior of VPS 9892 on Lime Sandstone

[0075]A lime sandstone specimen (sawn, commercially customary lime sandstone in blocks 5×5×5 cm, dried in a forced-air drying cabinet at 60° C. to constant weight and then cooled to room temperature in a laboratory for about 3 hours) is immersed in VPS 9892 for 2×5 seconds. Between the impregnating steps, the specimen is allowed to drip-dry for 30 seconds. Following the second impregnation, excess impregnant is dabbed off with an absorbent cloth. Subsequently, the test specimen is left to react at room temperature for about 1 week in the laboratory. Thereafter, the test specimen is split into 2 halves using a hammer and chisel. The fresh fracture surfaces are treated with an aqueous dye solution (Azorubin S). Hydrophilic regions are stained red, hydrophobic regions remain colorless, since they are not wetted by the aqueous ink. The uncolored regions show the depth of penetration. This is measured at different regions by means o...

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Abstract

An oligomer mixture of n-propylethoxysiloxanes, containing from 80 to 100% by weight of n-propylethoxysiloxanes having a degree of oligomerization ranging from 2 to 6.

Description

BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to specific mixtures of n-propylethoxysiloxanes, to a process for preparing them, and to their use.[0004]2. Description of the Background[0005]Alkyl-functional silanes and siloxanes are employed, for example, in the hydrophobicization of absorbent mineral materials.[0006]EP 0 814 110 A1 describes the preparation of catenated and / or cyclic C3-C18 alkylalkoxysiloxanes by a two-stage process starting from the corresponding alkyl chlorosilane, which is first esterified to the alkylalkoxysilane and then, secondly, the ester product undergoes controlled hydrolysis and condensation to give the desired alkylalkoxysiloxane product. In this process, more than 1 mol of water per mole of Si is employed for the controlled hydrolysis and condensation. Alkylalkoxysiloxanes obtained in this manner are generally in the form of a mixture of oligomers. Besides alkyl and alkoxy groups, the alkylalkoxysiloxanes...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C07F7/08C07F7/00C09K3/18C07F7/18C08G77/18C09D183/04C09K23/54
CPCC07F7/0859C07F7/0874Y10T428/2995C07F7/0838Y10T428/31663
Inventor STANDKE, BURKHARDMACK, HELMUT
Owner EVONIK DEGUSSA GMBH
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